An investigation of worn work roll materials used in the finishing stands of the hot strip mill for steel rolling

The surface failure characteristics of different work roll materials, i.e. High Speed Steel, High Chromium Iron and Indefinite Chill Iron, used in the finishing stands of a hot strip mill have been investigated using stereo microscopy, 3D optical profilometry, scanning electron microscopy and energy dispersive X-ray spectroscopy. The results show that the surface failure mechanisms of work rolls for hot rolling are very complex, involving plastic deformation, abrasive wear, adhesive wear, mechanical and thermal induced cracking, material transfer and oxidation. Despite the differences in chemical composition and microstructure, the tribological response of the different work roll materials was found to be strongly dependent on the material microstructure and especially the presence and distribution of microstructural constituents, such as the different carbide phases and graphite (in the case of Indefinite Chill Iron). Cracking and chipping of the work roll surfaces, both having a negative impact on work roll wear, are strongly influenced by the presence of carbides, carbide networks and graphite in the work roll surface. Consequently, the amount of carbide forming elements as well as the manufacturing process must be controlled in order to obtain an optimised microstructure and a predictable wear rate.

Can France really stop them? : A study grounded on the realist perspective about the French foreign policy towards Syria as the root cause of the Phenomenon of French Foreign Fighters

During the Syrian conflict the number of European Foreign Fighters has increased exponentially and has become an ever-growing concern for European policymakers. This phenomenon presents host of major security challenges for European policymakers and governments. Among European countries, France provides the highest number of citizens who have gone to Syria to fight against Assad´s regime. The French authorities have estimated that by mid-2014, over 700 French citizens have left France and travelled to Syria to fight. Historically France has had a relationship with Syria which started with its role as a border-drawing colonial power. Grounded in a framework of realism, that emphasizes nation-states as the primary actor within the international system, the analysis concentrates on the role of France´s foreign policy on the Syria as push factor for terrorism and radicalization. This paper attempts to determinate a specific correlation between the policy that France has been conducting towards Syria between 2000 and 2015, and the phenomenon of French Foreign Fighters. Findings suggest that France´s foreign policy towards Syria is the main root cause of the French Foreign Fighters phenomenon.